Dipped-bridged lamp shade or similar article and method of making the same



Jan. 7, 1936. M. GREENAN 2,026,939

DIPPED BRIDGED LAMP SHADE OR SIMILAR ARTICLE AND METHOD OF MAKING THE SAME Filed July 19, 1935 2 Sheets-Sheet l 4 i l Him ATTORNEY.

Jan. 7, 1936. M GREENAN 2,026,939

DIPPED BRIDGED LAMP SHADE OR SIMILAR ARTICLE AND METHOD OF MAKING THE SAME Filed July 19, 1955 2 Sheets-Sheet 2 4 56 4 WWW.

r 2 I f ATTORNEY.

Patented Jan. 7, 1936 UNITED STATES ATENT OFFICE DIPPED-BRIDGED LAMP SHADE OR SIMI- LAB. ARTICLE AND ll/[ETHOD OF ltIAKING THE SAME 11 Claims.

This invention relates to composition dipped and bridged continuous thin open work framed devices, and to methods of making the same.

One object of the invention is to provide a method for making a device of the character described, which method shall be easy, simple, convenient, rapid and relatively inexpensive in operation, reliable and efficient in use, adapted for utilization under simple conditions, and requiring little or no apparatus for its practice, and which method shall be applicable to articles of different sizes and shapes and for different purposes.

Another object of the invention is to furnish an improved method for bridging openings of substantially larger size than heretofore possible in devices of the type herein mentioned; this method can be practiced with the change or omission of certain steps, or substitution of steps for other steps, and with different frames and compositions, varied singly or conjointly.

A further object of the invention is to construct a device of the nature set forth having few and simple parts, and which is inexpensive M to manufacture, smooth, uniform and attractive in appearance, durable and reliable in use, of low inflammability; and having a continuous bridging film coating secured thereon by a simple dipping action. I V

The invention provides a lampshade having a nonstretching film or the like secured on a springable conoidal frame in a uniformly taut condition in all directions, and in such manner as to be connected in the frame by a single movement.

Conoidal frames are referred to herein as distinguished from cylindrical frames for the reason that cylindrical frames cannot be industrially bridged by my method invention unless the openings be less than 2 inches in maximum width. I have found that there must be some degree of conicity in the frame. Further, the panels or side opening sections of the frames must be arranged so that, in the inverted position, the excess liquid composition is' adapted to run off from the frame in a vertical plane, or so as not to run laterally with respect to a certain adjoining panel opening to break the film thereof. Then again, conoidal frames having open-- ings greater than one inch in maximum width must be inverted and bridged according to my novel method.

Other objects and advantages of the invention will become apparent as the specification proceeds.

With the aforesaid objects in view, the invention consists in the novel combinations and arrangements of parts hereinafter described in their preferred embodiments, pointed out in the Ge subjoined claims, and illustrated in the annexed drawings, wherein like parts are designated by the same reference characters throughout the several views.

In the drawings:

Figure 1 is a View in side elevation of a device 5 embodying the invention.

Figs. 2 and 3 are horizontal sectional views taken on lines 2-2 and 3-3 of Fig. 1, respectively.

Fig. 4 is an enlarged sectional view taken on 10 line 4-4 of Fig. 1.

Figs. 5 and 6 are enlarged upright sectional views taken on the respective lines 5-5 and 6-6 of Fig. 1.

Fig. 7 is an enlarged vertical fragmentary 15 sectional view taken on line 1--1 of Fig. 1.

Fig. 3 is an enlarged fragmentary upright sectional view taken on line 8-8 of Fig. 1.

Fig. 9 is a vertical diagrammatic view with parts in section showing an apparatus for practicing steps in the method of the invention.

Fig. 10 is a vertical diagrammatic view with parts in section showing a modified apparatus for practicing certain steps in the method of the invention.

Figs. 11 and 12 are schematic vertical views showing the liquid action in withdrawing the frame from the bath in inverted positions, respectively, with the paths of the dripping illustrated in dotted lines, to show how the film is broken in the latter case.

Fig. 13 is a horizontal sectional view taken on the line I3l3 of Fig. 11.

Fig. 14 is a diagrammatic View in inverted position of a frame all of whose open side panels and downward, and which cannot be bridged.

The advantages of the invention as here outlined are best realized when all of its features and instrumentalities are combined in one and the same structure, but, useful devices may be produced embodying less than the whole.

It will be obvious to those skilled in the art to which the invention appertains, that the same may be incorporated in several different constructions. The accompanying drawings, therefore, are submitted merely as showing the preferred exemplification of the invention. This application is a continuation in part of my patent application, Serial No. 727,246, filed May 24th, 1934.

Heretofore it has been known to coat articles by dipping the same in various solutions or mixtures such as lacquers. That a similar method could be used for the purpose of closing or bridging large openings to produce a wall for an article was not iznown, and was, in fact, considered inconceivable and impossible by those skilled in the art. In solving this problem I encountered another difiiculty in that while I was able to bridge the large opening of an individual panel, I found that the bridging film would break down in attempting to bridge the openings of a continuous or closed frame such as a lamp shade frame.

After lengthy experimentation with compositions having different solids and solvents and dif' ferent proportions thereof, I discovered the feasible industrial method of bridging a frame of the type described, this method residing essentially in utilizing any conoidal as distinguished from a precisely cylindrical frame, in upwardly substantially vertically withdrawing the frame in inverted position from the liquid composition bath, and in causing a dissipation of solvent vapors or preventing a concentration thereof above the bath, which vapors would otherwise cause breakage of the bridging film as formed on withdrawal of the frame from the bath.

Other features of the method invention may be mentioned, as, for example, that the invention includes the bridging of openings at least two inches in maximum width and of any length desired, and that the openings in the frame de sirably taper downwardly in the inverted position or are each of such average shape as to taper downwardly; further that the liquid bath must be relatively quiescent, although the frame may be rotated in the bath before Withdrawal to dislodge air particles; that the atmosphere in which the bridging is done ought not to be unduly humid; that the liquid preferably lacquer com position ought to be quite free of water; and finally that the speed of Withdrawal of the frame from the bath is such as desirably not to be instantaneous and yet not unduly slow since the bridg- 1 ing film will break in either case.

The liquid composition bath employed in my method ought to be of high viscosity and tenacity and of high drying quality, and is of the type that is preferably self hardening in ordinary atmosphere and at ordinary temperatures. Various compositions may be used, and any lacquer or airplane dope having the required viscosity and drying quality may be employed. Generally speaking, the tenacity, strength, or surface tension of the liquid vary as the viscosity, and I may employ a composition having a viscosity of '7 to 65 poises. The drying quality may be indicated as being such that a film of the liquid may initially harden within a period of 25 to 35 seconds to pro- .duce a skin approximately 0.0001 inch thick,

where the initial hardening is indicated by the cessation of flow or movement of particles or fine globules of liquid in the film as observed by the naked eye, and where the initial hardening is effected in ordinary atmosphere as above noted and free of concentrated solvent vapors from the liquid bath. Thereafter the article may be set aside for one to two hours to fully harden.

Concerning viscosity, various methods of determination are used. The figures reported are based on the so called Hercules falling ball method which is a standard method and is described in the booklet Nitrocellulose published by the Hercules Powder Co.

The poise is the scientific unit of viscosity. It is the shearing stress in dynes per square centimeter required to move either of two parallel planes, one centimeter apart relative to each other, with a velocity of one centimeter per second, the space bet-ween the planes being filled with the fluid. The approximate viscosity of water at 20 C. is one hundredth of a poise or one centipoise (1.005 cp.). Seconds Hercules, multiplied by the factor 3.77 give the corresponding viscosity in poises.

As the action of the composition coating bath is apparently physical and not chemical, many different compositions and such as employ different ingredients and proportions thereof may be used to fulfill the physical characteristics herein mentioned illustratively, particularly in regard to viscosity and rate of drying of an easily hardening liquid. Since the coating quality and strength of the composition are affected by the solids and solvents therein employed, and since the solids and solvents have a direct play upon each other, and are further dependent upon other factors such as atmosphere, size of openings, degree of taper of the frame, rate of withdrawal of the frame, thinness of the frame, it will be perceived that the characteristics mentioned and formulas hereinafter stated are to be interpreted in an illustrative and not in a limiting sense, and that the invention is entitled to a substantial range of equivalents. I have, however, in compliance with the requirements of the statutes indicated a guide herein sufficient to enable those skilled in the art to practise the invention as described or in modified forms.

Generally described, this invention in the novel coating method provided, deals with extremely delicate forces, which are impossible to measure and the direct efiects of which are difiicult if not impossible to observe in actual practice. Hence the explanation as to the precise action that obtains when the frame is removed in inverted position from the liquid bath is offered here as tentative. I find that considerable drippings run down along the upright wires that define the frame openings that are to be bridged, and these drippings tend to weigh down and break the film, since the drippings tend to flow rapidly in vertical paths and hence away from the conoidal film. Since, however, the openings taper downward, the film is not weakened, and may increase in strength. This unbroken film tends to deflect the drippings toward the upright frame wires. But if not inverted, the contraction of the film is toward the vertical path that the drippings tend to assume, so that the drippings break the film away from the frame. In flowing downward. the drippings ought to hang away from the panel uprights so as not to lie too much in the plane of the film, and the shape of the panels ought not to be such that the film flows laterally of a panel upright, so that lateral breaking pull on a film is avoided. In a continuous or closed frame, where films are formed on opposite sides of each upright wire, the liquid that is lifted arid hence the dripping is substantially greater than it would be if a single panel were being bridged. In bridging a frame in the inverted position, the action in forming the film may also be regarded as similar to that in forming the lower part of a bubble, with the pull against the surface tension decreasing as the bridging progresses. I have found that any degree of conicity is satisfactory, although the bridging can be effected with less liability to accidental breakage if the angle of the cone is substantial. metallic wire, wood, composition or the like of preferably 1 g inch in thickness or diameter and which may be as great as inch in thickness, I have not found that the thickness of the frame affects the bridging, although I have also bridged While I use a frame consisting of frames as thin as inch or even less; however, the frame should not be unduly thick since the excessive dripping along the same may break the film. If the frame is not withdrawn from the liquid bath in inverted condition, the dripping flows rapidly vertically downward away from the frame, and breaks the film or is conducive toward the breaking thereof.

The article or lampshade provided by this method is a complete finished device, in which the frame is wholly encased with the frame wires causing attractive rib formations and the solidified film being taut and strong and lying substantially in the planes of the frame wires. The film wall may have additional reenforcing coatings and ornamentation formed thereon.

While I have described my novel method with particular reference to conoidal articles such as lamp shade frames, it will be understood that certain features of the invention are also applicable to plane frames as hereinafter described.

Referring in detail to the drawings, Ill denotes a device, such as a lampshade, embodying the invention. The same may, for illustration, include a conventional wire frame having upper and lower rings H, i2 respectively, and upright angularly spaced struts i 3 interconnecting the same and being soldered or welded thereto. A pair of adjacent struts it together with the intervening sections of the rings ll, l3 form a frame section panel or polygon A, and the frame as a whole not only provides a multisection frame, but constitutes a Wholly continuous multiframe section structure. The rings ii, l2 may be of diameters as shown, the struts 23 being shaped or curved accordingly, if desired, so that the different frame sections diverge apart from each other downwardly.

The openings of each section A may be said to be continuous in the same general direction in the sense that the opening lies in a plane or curved surface, but not in a surface which is curved to the degree that it reverses itself, as such opening would not be continuously closed but rather open at an end of the frame.

It will be noted that the frame sections A and the frame structure as a whole are of an openwork character, and that all of the frame sections to be simultaneously bridged, extend in the same or generally upright direction. By the term open work as herein used, is meant not only a frame whose margin is continuously closed and relatively thin and wholly open at opposite sides or faces of the frame, but also a frame whose generally horizontal or nonupright margins, as defined, for instance, within the rings H and i2, are open to permit a free and unrestricted relative movement as between the frame and the composition on withdrawing the dipped frame from the composition; for instance, the rings l 5, i2 Whether horizontal or nearly so, ought to be substantially fully open and unobstructed.

Bridging each frame section A is a thin film it of the self hardened composition. This film may also encase the frame itself. As shown in Fig. 2, the individual film walls is have a curve ture less than that of the rings i and 2, at the region substantially central between the latter; as the rings ii, i? are approached the curvature increases until at points in proximity to said rings, the film walls it have curvatures approximately exactly the same as those of the adjacent rings, as shown in Fig. 3. This is shown as an indication of the physical characteristics and qualities of the liquid film, and the degree to which the same is influenced by the shape and proximity of the frame elements, in forming the hardened wall It.

In Figs. at to 7 is shown how the composition encases diiferent frame elements. Thus, in Fig. 7, the composition provides a tubular wall it for an end element of the frame, which tubular wall is slightly thinned at iii due apparently to the surface tension of the composition. In Fig. 4, the composition provides a tubular casing i? for an intermediate element such as a wire is of the frame, the wall of the casing I! being free of any thinned portion such as obtains at i 6. Consequently the casing ll may be stronger than that at It. This difference appears to be due to the fact that the casing l! is continuous at opposite sides with the film walls Hi.

In Figs. 5, 6 and 8 is shown further how the film walls adjust themselves to the contour and structure of the lamp shade frame. to Fig. 5, the tension in the wall element is re- According sults in an inwardly offset formation as at 18 adjacent to the rings ii, it, while the wall element IQ follows the elements E3 in closely parallel relation thereto. In Fig. 6, the film wall M at the region closely adjacent to an element I3 is in relatively central relation to the rings ii, i2 due to the proximity of the elements iii. In Fig. 8 is shown an arrangement of the film at the joint between a ring and an upright offset element indicating the closely conforming film wall structure 59 and its ability to adapt itself to irregularities. Further, the transition at a corner between offset elements such as 12 and i3 is shown by the curved fillet 2t. rially reenforces the film wall structure and similar results are obtained by the fillets at 2!, 22. The film wall closely and uniformly contacts the surfaces of the frame and this, together with the encasing character of the film about the frame elements assures a strong structure. VJhile the different frame elements are herein shown as round, other shapes, formations, and structures may also be used.

It will be understood that the entire article or lamp shade i8 is first encased by a coating of a liquid self hardening composition having highly volatile solvents, and may be again completely encased by a second reenforcing coating of a self hardening liquid whose solvents are neutral to the first coating. Since the first coating is completely hardened before the second coating is applied, the first coating is wholly and accurate to the contour of the frame and is not affected by any weight or tension exerted thereon by the second coating. The second coating may be of a less dense or viscous and less expensive mate" rial. Hence I have provided a bridged article such as a lamp shade, including a foundation coating and coatings for opposite faces thereof, with the coatings adherent to each other and affording a taut strong wall structure lying substantially in the planes of the Wire frame elements, and the coatings each completely encasing the frame.

A feature of the lampshade that the film walls i i intersect the tubes or casings i'i substantially diametrically; in other words, the portions l'i project substantially equally on opposite sides of the film wall. Hence the wires i3 lie in the plane of said film walls, and therefore do not cast shadows thereon, as would he the case if these wires were offset either inward or out' 'ard of said plane. This interrelation of the frame and film is also rendered possible by the sub The latter mate- LII stantial spacing between the upright frame elements and the upper and lower frame elements, permitting the film wall to follow the desired arrangement. The hardened film wall is perfectly and uniformly taut, and this quality may be aided by the relative convexity of elements such as H and I2; and more specifically, by reason of the fact that elements l3 lie along a concave plane, and elements ll, [2 along a different convex plane, to assure stretching of the central or intermediate portion of the film of each panel.

An essential feature of the invention is that the film is highly taut bo'th transversely and longitudinally and hence tends to spring the frame wires. But since the film hardens in simultaneous contact with the upright and transverse wires, all stresses are automatically in equilibrium, and since the upright wires are tightly encased in the jointless film, no relative slippage can occur, so that a permanently well balanced,

reliable structure is produced. This is impossibleto obtain in any other lampshade. A nonstretching covering could not be industrially secured to a conical lampshade frame with uniform tautness at all points in any other manner.

Referring now to the means for making the device I0, 25 denotes a part of an apparatus that may be employed. The same may include a tank 26 for a bath 2! that is used to coat the frame. The latter may be indicative of any suitable open work device 28, and may be releasably rigidly connected in any suitable manner to a rod or spindle 29, as at 30, with the rod being desirably vertical and remote from the frame, as by being in coaxial relation with a lamp shade frame. Where the latter is provided with a usual sustaining cross element at its upper small end, the rod 29 may be conveniently detachably clamped to such cross element. The rod 29 may be manipulated wholly manually, but, if preferred, may be mounted for vertical reciprocation in any suitable device or bearing 3|, which may also include a drive operated as by a shaft 32 for rotating the spindle 29, at will.

Since the tank is filled with the self hardening composition substantially to the top thereof, solvent vapors are not confined but become quickly dissipated into the atmosphere so as not to attack the film as it leaves the bath.

In the practice of my novel method, the frame 28, after being rigidly connected to the rod 29 is inserted into the quiescent bath 21, in a manner such as not to unduly agitate the liquid. Then the rod 29 may be rotated to spin the frame for 10 or seconds at a suitable speed, for example, of about 250 revolutions per minute, after which the rod 29 is moved upward in an accurate vertical direction to raise the frame 28 out of the bath. A thin film of the liquid now bridges all the generally upright openings of the frame, in the manner hereinbefore described, and is permitted to air dry and harden at ordinary room temperatures for about one to two hours, care being taken that the atmosphere is not unduly humid. After the film has hardened, the device may be redipped as hereinafter described, to increase the thickness and strength of the film. The additional coatings are naturally easier to produce, and it is merely necessary that the subsequent bath shall have a different solubility so as not to dissolve away the film.

An important factor in the method is that the horizontal openings provided by the rings II and I2 are not bridged but remain open, because the weight of the liquid and of drippings readily breaks any film that may tend to build up for these openings. Any drippings that may remain on the lower edge of the frame may be wiped away immediately upon removal of the frame 5 from the bath, without breaking the bridging film.

In Fig. 10 is shown a modified apparatus 33 for the practice of the invention. This apparatus may include a tank 34 only partially filled with 1 the liquid coating composition, as up to a variable plane .35 that is considerably below the top edge 36 of the tank. To remove the solvent vapors that would otherwise accumulate in the upper part of the tank above the liquid surface 1.,

35, a conduit 3! may extend around the tank in communication with the upper portion thereof as by means of spaced openings 38, and this conduit being connected to an exhaust duct 39. With this arrangement various depths of the ill) liquid bath can be used, and in operation liquid need not be constantly added to the bath as would be necessary in the case of the apparatus to prevent accumulation of solvent vapors. A frame 40, similar to that shown at H] and at 28 2:; may be coated, by being dipped and manually withdrawn with the aid of the central rod 4| rigidly secured at 42 to the frame in axial relation thereto. Rotation of the frame may or may not be practised. The frame 40 may have straight side wires tapering downward according to a small angle.

In Fig. 11 is illustrated the action of the drippings of the viscous liquid coating composition in upwardly substantially vertically withdrawing the conoidal open work thin frame 43 from the liquid bath 44. At the upright frame wires, the dripping follows the paths indicated at 45 and tends to pull away from the wires so as to follow a gravitational path, but is partially restrained 4.0 by the bridging films denoted at 45. As indicated by the arrow d, the dripping exerts an outward lateral force, while the bridging film exerts an opposite inward force indicated by the arrow 1.

In Fig. 12 is shown the action of the dripping 45 when the same frame is removed in upright noninverted position from the bath 44. The dripping then falls away from the upright frame wires 41 and follows a substantially direct vertical path as at 48. Film walls such as indicated at 46 do not form or are broken almost as soon as formed whether by reason of the downward divergence of the wires 48, or the pull of the dripping, or because the dripping exerts an inward lateral force D on any film that may form, and the film because of its tenacity or surface tension also exerts an inward lateral force F, so that both forces D and F act to pull the film away from the frame to break contact therewith.

Differently stated, the forces (1 and as in Fig. 11 act in opposition so that the film is not torn away from the frame, especially if the frame is being withdrawn from the bath in a reasonable period of time to afford a slow drip flow and to render the film an opportunity to move toward 6 the frame as the film is drawn out from the bath. The forces D and F, however, supplement each other in tearing the film from the frame.

As further indicating the effects of conicity, I

have found that frames as herein shown, but

perfectly cylindrical in shape cannot be bridged as an industrial proposition because of breakage of the film at one or more panels, except if the panel openings are less than 2 inches in maximum width. Some degree of conicity, however small, is necessary. The advantage ofconicity appears to be indicated in Fig. 13 since a portion of the drippings, indicated at 5B, is outside the plane of the film walls 46 and can flow down rapidly without exerting a direct disruptive force on the film 48. As the dripping leaves the frame, the films 36 contract inward into direct contact with the upright wires 47 of the frame 43.

In Figs. 14- and 15 are shown inverted conoidal lampshade frames fat, 52 to indicate further the effects of panel shapes in bridging openings whose greatest maximum width is at least 2 inches. In the frame 5|, the open side panels 54 taper moderately upwardly, and downwardly toward each other, and the intervening downward tapering panels 55 are initially closed, as by fabric, parchment or the like secured to the frame. The openings 54 can be bridged by the method hereinbefore described. In the frame 53, all upward and downward adjoining panels 56, 51 respectively are open, and this frame cannot be bridged. Hence it appears that the upright panel edges need not necessarily lie in vertical planes, as in the case of the frames hereinbefore mentioned, but may assume an angle thereto of say 10 to 15 degrees. However, the film must apparently not be subjected to a lateral pull at the frame uprights by the drippings. Thus in device 53, the film at 51 will be subjected to such a pull, while in the device '52, corresponding panels 55 are initially closed, and While dripping tends to fiow toward the film at 56, the film is also deflected outward from the plane of the film as indicated in Figs. 11 and 13. In Fig. 14 it is seen that the drippings will flow symmetrically with respect to opposite symmetrical edges of frame elements 55, but in nonsymmetrical relation to the wires 58, or the corresponding opposite edges thereof. In the frames 28, 4B and 43, the upright wires are symmetrically arranged, and lie in vertical radial planes so that they are readily bridged.

The panel openings should be uninterrupted from top to bottom for bridging. For example, if a frame ring were disposed intermediate the top and bottom rings to form upper and lower sets of openings, one set would have to be bridged and then protectively coated before the other set.

The explanations of the action in removing the frame in inverted condition are offered herein in a theoretical and not in a limiting sense.

The invention is applicable to the making of co-noidal articles generally, for instance, articles such as hats and umbrellas. In articles of this character the ring such as I I may be made relatively small in diameter so as to be bridged in the same operation used for bridging the side panels, or if this ring be too large to be so bridged, the films for the side panels may be coated with the. second coating and the ring H bridged in any suitable manner without causing the solvents in the first bridging compound to break the connection between the film walls M andthe ring l For an umbrella, the wires It may be swingably connected to the ring it and the ring i2 may be removably engaged with the wires 13, so that the film i l may be undercut and reenforced along its free edges by a suitable binding, and with the ends of the wires l3 projecting beyond the same as in the case of an ordinary umbrella. The flexibility of the film walls I 4 will permit the umbrella to be conventionally opened and closed. At the ring II, the film walls may be severed from this ring and a sheet of material may be extended over the ring and cemented to the film walls adjacent to the ring II for the desired movability. Thus any frame shown herein may be regarded as a skeleton for making an umbrella.

In every case, the frame as removed from the lacquer bath in inverted substantially vertical position should be so maintained for a period of at least approximately /2 to 1 minute or as long as necessary to permit all drippings to leave the frame; and preferably the frame is maintained in this position until the film has substantially hardened.

It is thus seen that my invention provides a process applicable to many different kinds of articles and residing in a combination of the following steps in conjunction with the following interrelated circumstances. A liquid coatingcomposition is used having high tenacity and Viscosity and a high drying quality, sufficient to bridge openings at least approximately 2 inches in width. More specifically, the drying quality is such that a flow of fine particles or globules in the bridging film can be observed by the naked eye to cease within a period of say 20 to seconds of time. If the time be less, the viscosity may be toogreat to permit the liquid composition to be worked; or the rate of drying may so excessive that continued renewal of the composition bath may be required to avoid undue plasticity; or a combination of these unsatisfactory factors may obtain. If the time be greater, the liquid composition bath may be too thin to bridge, and the drying quality may be too low to cause some degree of rapid increase in viscosity or partial solidification to prevent breakage of the film due to its own weight or the constant running down of the liquid in the. film and resulting thinning and breaking thereof. Of course this time element is construed with relation to an atmosphere that is not charged with solvent vapors that have evaporated from the composition, and which would interfere with the drying of the film and tend to maintain the film liquid with resulting breakage thereof. When the atmosphere is so charged with the solvent vapors, I have found that the films collapse within 1 to 2 seconds after removal of the frame. from the bath. Hence it appears that the film must instantaneously begin to dry and harden upon removal of the frame from the bath, and substantially as it is being so removed. To permit the solvent vapors to re-' main concentrated in the bath tank such as 34 as distinguished from the substantially full tank 26, without removal of the vapors from the upper region in the tank 34, would require the. use of a composition of such high viscosity and drying quality as would increase the expense and interfere with the quantity production of the lamp shade.

The viscosity of the liquid composition may vary within the illustrative range of 7 to 65 p'oises.

In general, the higher the viscosity, the greater the tenacity of the. film, and the easier it is to bridge the frame, but with unduly high viscosities' the bridging becomes difficult and the film breaks due to the Weight of the liquid. If the viscosity is reduced the liability to breakage of the film as formed is greatly increased and as the viscosity is unduly reduced, it becomes impossible to bridge the openings of the size herein mentioned. The viscosity naturally has some effect upon the drying quality but this effect may for practical purposes be disregarded.

Hence the physical character of the coating compound is amply defined, if the viscosity be considered in conjunction with the drying quality as indicated by the fact that the film formed is approximately 0.0001 of an inch, and that the minute particles or globules in the liquid film, as observed by the naked eye, cease to run in the film in a period of 20 to & seconds in an atmosphere free of excessive vapors that have the capacity of dissolving or thinning the film.

The time for removal of the frame from the composition may be greater for larger openings and less for smaller openings. In general, a time of 8 to 10 seconds per foot length of the frame is most satisfactory, but this time may be as low as two or three seconds and as high as to seconds per foot length. Here again the viscosity and drying quality of the liquid composition are factors to be considered. If these factors are substantially high, the film is more easily broken as removed and as the time for removal is increased because undue solidification occurs at the film; and if the time be substantially instantaneous the film will be torn. Excessive increase in the time of removal of the frame will in a y case cause breakage of the film; and instantaneous removal will have the same effect.

The liquid composition bath must be quiescent although the frame may be rotated therein about a vertical path to dislodge air particles. This rotation may be dispensed with. In any event, the frame is not rotated while it is being removed, but is withdrawn in a single upright path, that is, without lateral movements which would cause breakage of the film as formed. The said path is for the same reason preferably vertical or nearly so, and the frame is maintained with its axis vertical and, in any case, in such manner as to avoid a substantial angle with the vertical since that would result in lack of liquid equilibrium in the bath and cause uneven or improper stresses in the film as it is being formed.

The frame itself affords one of the circumstances which is directly related to the method invention. This frame is of hollow open work thin sheet or wire like material so as to readily cut the viscous liquid without undue agitation and without lifting out excessive material for undue dripping. The frame is conical in any desired degree, or in the form of a frustum of a cone, and is continuous or closed in the horizontal direction, with side openings forming panels, which openings taper upward or whose average shape is such as to afford an upward taper. These openings are bridged, and the size thereof, to which the problems solved by this invention relate is such that the openings are not less than approximately one inch in maximum width and are preferably greater, and of any desired length.

The relatively clean frame referred to is dipped into the liquid bath in any desired position and is withdrawn in inverted position. To avoid undue agitation of the liquid, the frame may be dipped in the same position as it is withdrawn. By the practice of the method herein described, I have been able to bridge openings up to 5 and 6 inches in width. After the film is formed upon the withdrawal of the frame, the film is permitted to thoroughly air harden for a period of one to two hours. An atmosphere of excessive humidity is preferably avoided at all times, as it has a deleterious effect upon the film.

The frame should be relatively rigid so that the frame elements shall not unduly spring and break the film on its removal from the viscous composition bath.

After being thoroughly hardened, the second coating is applied by dipping the bridged frame into a'second different composition. This second dipping may be done in any desired manner, period of time and position of the frame, it being merely necessary that the second composition shall not dissolve away the foundation film. Since the frame openings are already bridged, the application of the second coating presents no problem. However, the second dipping may be done in the same manner as the first, or in noninverted position, or repeated dippings in successively inverted and noninverted positions can be practised.

It may be noted that the frame need not be absolutely continuous or closed but may have a longitudinal split or opening therein, and still fall within the scope of this novel process, it being sufficient that the frame be substantially continuous.

The liquid composition used for the first or foundation coating is preferably one that is relatively noninfiammable, and may have as its base an organic ester of cellulose, such as cellulose acetate, although the more inflammable cellulose nitrate may also be used, though with less eificient results. The composition may also comprise an ingredient to prevent crinkling of the hardened film.

My invention also comprehends the bridging of single or individual panels that are at least 4 inches in width and of any desired length. These panels are thin, open and may be rectangular or tapered. If tapered they are preferably withdrawn from the bath in inverted position, but

they can be withdrawn in any position and in a generally upright direction at an angle desirably not in excess of approximately 30 degrees with the vertical, and preferably in a true vertical direction. The method may in all other respects be precisely the same as that for a lamp shade frame. A coating composition of a viscosity somewhat higher, say between 25 to 65 poises is desirable when the openings to be bridged increase in size to a width materially in excess of one inch.

By way of illustration of a liquid composition that may be used in the bridging operation contemplated by my invention, I disclose the following formula, in pounds of weight:

Pounds Cellulose acetate 2 l Triphenyl phosphate 8 Ethyl para toluene sulfonamid 8 Dibutyl tartrate 1 Diacetone alcohol 4 Acetone 7 6 This formula will be designated hereinafter as Formula A.

An alternative formula. is as follows:

Pounds Cellulose acetate 21 Triphenyl phosphate 8 Plastol resin #13 8 Dibutyl tartrate 1 Diacetone alcohol 9 Acetone '72 Plastol resin #13 is a secret formula manufactured by Interessen Gesellschaft fur Chemische Industrie, a German concern, and is sold by Advance Solvents & Chemical Corporation, of New York City, New York, as the representative of the German concern. Plastol resin #13 has certain advantages in my composition, as it has a high degree of body forming constituents, and yet is soft and stretchable when hardened. However, it is seen that ethyl para toluene sulfonamid is a substantial equivalent therefor, and I prefer that the percentage of diacetone alcohol be reduced and that of acetone increased.

Triphenyl phosphate, ethyl para toluene sulfonamid, plastol resin #13, and dibutyl tartrate are softening fillers which do not unduly increase the viscosity of the composition. Diacetone alcohol and acetone are solvents. The cellulose acetate is affected so that any possible tendency to crinkling is avoided, which it would have if the softening agents were not used.

I may also use the following formula, which while good, is not quite as satisfactory in unbreakability as the foregoing:

Pounds Cellulose nitrate 14 Camphor 6 Castor oil 4 Dibutyl phthalate l Hydrogenated alkylester of abeitic acid 4 Ethyl acetate 30 Toluole 22 Ethyl alcohol 9 Acetone 2 Pentasol acetate 3 Secondary butyl alcohol 5 It may be noted that the first five ingredients provide the film forming solids, while the remainingredients are volatile and evaporate to leave the film.

A more satisfactory nitrate formula is the following, hereinafter denoted as 33:

Pounds Cellulose nitrate (about 3 seconds Hercules)- l8 Camphor"; 7 Castor oil 3 Tricresyl phosphate 3 Denatured alcohol 8 Methyl acetate 20 Ethyl acetate 4 Acetone 30 Pentasol acetate 3 Secondary butyl alcohol 3 The cellulose acetate, which may be obtained of various viscosities, is so chosen or blended by using cellulose acetates of various viscosities as to give a final lacquer having a desired viscosity.

. The same applies to cellulose nitrate.

stantly due to evaporation of solvents while the bridging is in progress, and further, the required viscosity range will vary with the size of opening to be bridged, the speed of frame withdrawal, the atmosphere into which the withdrawal occurs for drying, the thickness of the film, as whether the same be 0.0001 inch, or less, or several times greater, the conicity of the frame, the shape of the panels, symmetry of the frame and of the paths of the drippings, and other factors. Likewise the required rate of drying will be affected by all of these factors since it also affects the strength of the film as formed.

Compositions having as a base a nitrate of cellulose, or a gum may also be used; for example, an ordinary commercial lacquer from which a portion of the solvents has been evaporated, and a gum or latex added in uniformly intermixed condition may be used for bridging spaces up to 3 inches in width.

The film produced is of substantially uniform thickness and is of sufficient tensile strength so that it will not be broken by the subsequent dipping in the viscous coating composition that is used to reenforcethe film.

In order to illustratively indicate the possible viscosity ranges, I suggest the following, in poises, for formulas A and B for openings of difierent maximum widths in inches as follows:

Formula A Opening size Lower limit Upper limit Formula B Opening size Lower limit Upper limit It may be possible to increase these ranges slightly by diminishing the lower limit and raising the upper limit, depending on the composition and the other factors hereinbefore mentioned. The viscosity for 1 inch openings may vary in poises between 5 and .5 with Formula A and between 9 and 60 for Formula B. All viscosities herein mentioned are considered to be high as compared with usual lacquer practise.

It will be noted that Formula B requires a substantially higher viscosity, for example, by 50%, than Formula A. It may be noted that the viscosity of Formula A is approximately 40 poises.

That of Formula B, as herein given, is, however, lower, and is approximately 26 poises (7 second Hercules) Viscosities are taken at 70 F., and my process may be performed at ordinary room temperatures.

It will be seen that if any one of the viscosities given for the upper limit be taken, all openings can be bridged. Thus for openings of 2 to 6 inches, any viscosity for Formula A of from 50 to 65 may be used; and for Formula B, any viscosity from 65 to may be readily used.

The best practice is to use, for an opening of a given size, a viscosity approximately one-third of the range above the lower limit of viscosity. Thus for a 2 inch opening, using Formula A, the viscosity is preferably 10 to 15 poises. If a viscosity in the neighborhood of 50 is used with Formula A, the film becomes uneven, and less clear, as it tends to entrap and hold air bubbles; but is otherwise satisfactory. Ordinarily the more viscous liquid will require a slower drying quality, to afford the film more time to smooth out and release air bubbles. A less viscous liquid requires more skill in handling, but produces a film of superior smoothness and clearness.

In actual practise, a composition of a viscosity of 70 to 80 poises for Formula A, for example, is made up and may be kept in stock. In use, the composition may be thinned down by adding the desired solvent, while testing the lacquer with the frame that is to be bridged.

It will be noted that Formula A, having a viscosity of to or 50 poises may be used to bridge openings from 2 to 6 inches. The formula containing the plastol-resin has substantially the same rate of drying as Formula A, so that substantially the same viscosity may be used for both. For Formula B, a viscosity of to or will be satisfactory for all openings. Hence Formulas A and B have a common ordinary range of utility of approximately 40 to 50 poises, and a common maximum range of 40 to 65 poises.

It will be clear that the bridging or foundation film may be either an acetate or a nitrate. It is preferred to use an acetate bridging film, because there are fewer solvents that will cut or break an acetate film than a nitrate film.

A reenforcing nitrate coating is applied to an acetate bridging film, and vice versa, so that the reenforcing coating shall not cut or dissolve the bridging film. After the nitrate coating is applied, a final top coating of the acetate composition may be applied for additional reenforcement and to avoid the infiammability of thenitrate coating. Any lacquer or other coating material having a viscosity of 2 to 4 poises may be used and will assure smoothness.

A gelatin coating may be used instead of the nitrate and acetate coatings, but it does not afford as smooth a surface. Moreover, gelatin must be applied hot. By way of illustration, 2. gelatin coating composition having by weight approximately 4 parts of gelatin, 4 parts of water, and 2 parts of a drying retarding agent such as glycerine is satisfactory.

I claim:

1. The method of making composition dipped open ended but otherwise closed articles having a plurality of side windows each at least one inch in maximum width, including dipping a conoidal thin open work frame wholly into a liquid com position bath of high drying quality and having a viscosity of between 5 to 9 and 65 to poises as lower and upper limits, respectively, maintaining said bath relatively quiescent, withdrawing said frame from the bath in an upward path with the frame in an inverted but otherwise upright position to bridge the side openings of the frame, the withdrawal being effected at a relatively slow rate, and maintaining the atmosphere into which the frame is withdrawn, including the atmosphere immediately above the said bath, relatively free of concentrated solvent vapors liberated from the composition, and the frame being further characterized in that it includes upright frame elements defining the side openings, which upright frame elements are arranged to cause drippings of the composition to flow away from exterior opposite edges of the frame elements in a relatively symmetrical relationship thereto, as set forth.

2. The method of making a lamp shade or the like, having a thin open work wire frame open at the top and bottom and having side openings at least one inch in maximum width bridged uniformly by a hardened composition material, said frame being of conoidal form and having upright wire elements that define generally downward tapering side openings extending substantially from top to bottom of the frame, dipping said frame wholly into a composition liquid bath, withdrawing said frame from said bath in an upward substantially vertical path with the frame in inverted substantially vertical position, to bridge said side openings and with the composition being of such high viscosity and drying quality as to cause the bridging film to begin to dry substantially as withdrawn from the bath, maintaining said bath relatively quiescent during the withdrawa-l, causing said frame as withdrawn to enter an atmosphere relatively free of concentrated vapors solvent to the film, including the atmosphere substantially immediately above the bath, and permitting a free flow of drippings to said bath as the frame is removed.

3. The method cf making a lampshade or similar article having a thin open work conoidal frame with upright wires defining side panel openings extending continuously from the top to the bottom of the frame and being at least one inch in maximum width, including dipping said frame wholly in a liquid composition bath having a high drying quality and a viscosity within the range between 5 and 10 poises and 65 to 100 poises as lower and upper limits respectively, withdrawing said frame from said bath in an upward relatively vertical path with the frame maintained in inverted relatively vertical position, maintaining said bath relatively quiescent while so withdrawing the frame, and the withdrawal being effected at a relatively slow rate into an atmosphere substantially free of concentrated vapors solvent to the bridging film of the composition for the side openings of the frame.

4. The method of making a lampshade or similar article having a relatively thin open work conoidal frame with upright frame elements forming panels that define marginally closed side openings at least two inches in maximum width, the elements being so arranged that drippings therealong will flow in substantially symmetrical relation along each element with respect to adjoining panels, in the inverted vertical position of the frame, including dipping said frame into a bath of liquid composition of substantial drying quality and viscosity to cause the composition to fill said openings, upwardly relatively slowly withdrawing said frame from the bath with the frame in an inverted position with the axis thereof upright, into an atmosphere substantially free of concentrated vapors solvent to the composition, and maintaining the bath relatively quiescent during the withdrawal of the frame.

5. The method of making a lampshade or similar article having a relatively thin open work conoidal frame with upright frame elements forming panels that define marginally closed side openings at least two inches in maximum width, the elements being so arranged that drippings therealong will flow in substantially symmetrical relation along each element with respect to adjoining panels, in the inverted vertical position of the frame, including dipping said frame into a bath of liquid composition of substantial. drying quality and viscosity within the approximate range between 5 and 9 and 65 to 100 poises to cause the composition to fill said openings, upwardly withdrawing said frame from the bath in a substantially vertical path with the frame maintained in an inverted substantially vertical position, the withdrawal being effected at a relatively slow rate into an atmosphere substantially free of vapors that are solvent to the composition, and permitting drippings of the composition to freely flow down along the upright elements in the inverted approximately vertical position of the frame substantially along said path.

6. The method of making a lampshade or similar article having a relatively thin open work conoidal frame with upright frame elements forming panels that define marginally closed side openings at least one inch in maximum width, the elements being so arranged that drippings therealong will fiow in substantially symmetrical relation along each element with respect to adjoining panels, in the inverted vertical position of the frame, including dipping said frame into a bath of liquid composition of high viscosity, upwardly relatively slowly withdrawing said frame from the bath in a substantially vertical path with the frame in an inverted substantially vertical position, into a drying atmosphere that is substantially free of concentrated vapors solvent to the composition, the composition having such high drying quality that the liquid in the film formed to bridge said openings ceases to fiow in the film within approximately 20 to 40 seconds after withdrawal from the bath, and the latter being maintained relatively quiescent during the withdrawal of the frame.

'7. The method of making a lampshade or similar article having a relatively thin open work conoidal frame with upright frame elements forming panels that define marginally closed side openings at least two inches in maximum width, the elements being so arranged that drippings therealong will flow in substantially symmetrical relation along each element with respect to adjoining panels, in the inverted vertical position of the frame, including dipping said frame into a bath of liquid composition having a viscosity within the range of approximately 7 to 65 poises and maintained relatively quiescent, upwardly relatively slowly withdrawing said frame from the bath in an approximately vertical path with the frame in inverted approximately vertical position, into a relatively drying atmosphere substantially free of concentrated vapors solvent to the composition, whereby said openings are bridged by a thin film of the composition, and the composition having a high drying quality.

8. The method of making a lampshade or similar article of the type set forth having film bridged side openings at least one inch in maximum width, including dipping a conoidal open work frame into an acetate lacquer bath of relatively high viscosity and drying quality, maintaining said bath relatively quiescent, upwardly relatively slowly withdrawing said frame from said bath in a substantially vertical path to bridge the side openings in the frame, maintaining said frame in inverted substantially vertical position during the withdrawal and fiow of drippings along the frame, maintaining the atmosphere into which the dipped frame is withdrawn substantially free of concentrated vapors solvent to the film, permitting the film to harden, and then coating the film with a nitrate lacquer.

9. The herein described composition dipped lampshade for floor and table lamps, including a conoidal wire frame having upper and lower wires interengaging a series of spaced upright wires, and a one piece self hardening film hardened on and continuously encasing said wires and bridging the openings therebetween, so as to provide otherwise self sustaining film walls interconnecting the encasing film portions, and the spacing between the upright wires being at least one inch to cause the film walls to intersect the 10 upright encasing film portions diametrically, so that the projection of shadows by the upright wires on the film walls is avoided, said film walls being substantially thinner than the frame wires and having thickened connection with the film casings, and a reenforcing coating completely encasing said film and formed from a composition nonsoluble to the film.

10. An inverted composition dipped lampshade of the character described having a truncated cone wire frame open at the top and bottom thereof and defining upright openings lying in different planes and extending continuously from the upper to the lower edge of the frame and being continuously marginally closed by the frame wires, and the openings being at least two inches in width, and a one piece self hardened continuous film directly formed and hardened on the frame to bridge said openings continuously, and the frame having its upright wires between said openings encased by the film and lying substantially in the plane of the bridging film portions, and said film being substantially thinner than the frame wires, and the latter constituting the sole support for the film.

11. The herein described seamless composition dipped article including a conoidal relatively rigid wire frame comprising upper and lower wire rings and upright wires interconnecting said rings to provide side openings at least one 40 inch in maximum width, and a one piece self hardening film adapted to be connected to the frame by dipping in a liquid composition, said film including a film portion continuously encasing the wires of the frame and the connections thereof, said film being hardened on said frame substantially in the medial planes of said wires to provide a relatively nonstretchable film contracted on the frame and bridging said openings so as to exert tension on the frame in the longitudinal and transverse directions, with the tension tending to spring the frame wires toward each other, the bridging film being of substantially uniform thickness throughout and being substantially continuously connected to the wire encasing film portion so that the film for each of said openings is held in positive fixed relation to the adjacent wires, with the film for each opening uniformly longitudinally and transversely stressed to maintain the film fully permanently taut throughout, whereby the article is balanced in its stresses and relative slippage between its component parts avoided.

MAX GREENAN. 

